Among the monumental developments and reunions of this past Saturday's 'Doctor Who' 50th anniversary special, "The Day of the Doctor," longtime fans of the BBC sci-fi series were given a treat, not only in seeing the 12 generations of Time Lords unite for one singular purpose, but also a glimpse into the future as upcoming star Peter Capaldi was given his official 'Doctor Who' debut!

Spoiler warnings from here on out, but however much 'Doctor Who' 50th anniversary special "The Day of the Doctor" may have tried to keep its story contained between Matt Smith's 11th Doctor, David Tennant's 10th, John Hurt's "War Doctor" (and even a brief reappearance from Tom Baker's legendary 4th Doctor), it seems the smorgasbord of Time Lord appearances in the event episode's climax couldn't exclude the soon-to-be 12th Doctor, as portrayed by upcoming star Peter Capaldi!

We saw relatively little of the latest Doctor, who will receive his official indoctrination (see what we did there?) during the 2013 Christmas special to replace current star Matt Smith, but Capaldi's brief appearance proved no less intriguing in teasing the next incarnation of our beloved time traveler.

While the future adventures of the 12th Doctor remain to be seen, behold his arrival in the brief "Day of the Doctor" clip above, and tell us in the comments what you thought of the landmark 'Doctor Who' 50th anniversary special! Are you ready to accept Peter Capaldi as the next generation of 'Doctor Who'?

[Editor's Note: This article was originally written identifying Peter Capaldi as the 13th Doctor, given John Hurt's semi-official status by the end of "The Day of the Doctor," and Capaldi's referral as "13" in the clip above. However, if Steven Moffat says 12, that's good enough for us.]